Various proposals have been made to reduce the weight of vehicle bumpers while increasing their energy absorbing characteristics thereby mitigating damage during collisions. Concurrent proposals often include the employment of exterior airbag systems to provide additional protection while maintaining an overall relatively lower vehicular weight.
One approach has been to mount compressible energy absorbing plastic material on a rigid bumper beam. In order to provide secondary energy absorption in such systems it has been proposed that a collapsible plate like member be embedded in the compressible energy absorbing plastic material as shown in U.S. Pat. No. 3,856,613. While suitable for their intended purpose, such systems add weight to the vehicle and require special tooling to faun the compressible energy absorbing plastic material around the components which form the collapsible plate-like member.
Another approach, shown in U.S. Pat. No. 3,656,791 for example, provides a vehicle bumper with a fascia covering an inflatable air bag. The air bag is located behind the fascia during normal use. On impact the air bag breaks through the fascia destroying it and exposing the air bag to damage as it extends beyond the fascia to be directly exposed to an impacting object. Upon operation there is a potential of rupture of the air bag on impact. Such rupture releases the inflating medium in an uncontrolled manner such that the device no longer provides impact absorption under controlled conditions. Additionally, during normal operation there is no provision for releasing the fluid or gas from the air bag to provide a controlled rate of energy absorption which will avoid damage to the bumper system.
Accordingly, it would be an improvement in the art to develop an airbag system or collision dampener that not only reduces the weight of the vehicle but also reduces the mechanical damage of the vehicle in the event of a collision.